13 Ram 5.7 short runner valve

[greasybob]

This one had me going for a while. I had a 13 Ram 1500 5.7 with a code P1004 , the intake short runner valve not in the desired position. The code was intermittent but it could be duplicated on a wide open throttle run most once in a while. the scanner show frequent drop outs of the position signal but this alone did not set any codes but probably not normal. Next I did a functional test of the actuator, the test passed and the scanner showed the position movement. Interesting though that with just the key on and engine off there were no drop outs in the signal. Next I Back probed the actuator signal wire. the actuator indicates it's position to the PCM by sending a pulse width signal that varies it's duty cycle time. This signal showed a very few intermittent drop outs that did not seem to match what was showing on the scanner. So replaced the actuator. No success, still was showing drop outs. Hmmmm ? Maybe the signal wire is picking up interference from somewhere or shorting to ground ? Could not find any evidence of either. Wiggle test of the harness was inconclusive too. Next step ? Clip the wire at the actuator and at the PCM and run a new one. Bingo !!! No more dropouts. Problem must be in the harness some where. There is one potential rub spot on the right rear of the engine but no damage was visible. Gonna leave the the replacement wire secured in place for now and see if the customer wants to spring for a new harness or wait and see if there is a recurrence.